Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2003
Comparative Study Clinical TrialMidazolam premedication in children: a comparison of two oral dosage formulations on sedation score and plasma midazolam levels.
We compared two available oral formulations of midazolam with respect to sedation score and plasma midazolam levels in pediatric surgical patients 2-10 yr old. The commercially available oral syrup was compared with a mixture of the IV midazolam preparation in Syrpalta syrup at an equivalent concentration of 2 mg/mL. ASA status I-II patients were randomly assigned to receive 0.5 mg/kg of either the commercial syrup (Group 1) or the prepared mixture (Group 2) as anesthetic premedication. ⋯ Plasma midazolam levels were acquired exactly 45, 60, and 90 min after administration. Group 2 patients had a significantly lower median Observer's Assessment of Alertness/Sedation score (Group 1, 17; Group 2, 15) at 30 min (P < 0.03) and significantly higher mean plasma midazolam levels at all three acquisition times (mean +/- SD) (45 min: 63.1 +/- 23.9 ng/mL, Group 2; 43.4 +/- 19.6 ng/mL, Group 1; 60 min: 45.8 +/- 18.2 ng/mL, Group 2; 30.8 +/- 17.9 ng/mL, Group 1; 90 min: 28.9 +/- 12.6 ng/mL, Group 2; 21.0 +/- 8.9 ng/mL, Group 1) (P < 0.02). We conclude that IV midazolam mixed in Syrpalta syrup yields more reliable sedation and correspondingly higher plasma levels than an equivalent dose of the commercially formulated and marketed preparation.
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Anesthesia and analgesia · Feb 2003
The duration of immobilization causes the changing pharmacodynamics of mivacurium and rocuronium in rabbits.
In the clinical setting, in patients with a cast, it is not known whether the monitoring of the neuromuscular paralysis induced by either mivacurium or rocuronium in the contralateral limb is the correct interpretation. We compared the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium in 56 anesthetized rabbits immobilized in a plaster cast for 2, 4, and 6 wk. Train-of-four stimuli were simultaneously applied every 10 s to both common peroneal nerves, and the force of contraction of both tibialis anterior muscles was measured. ⋯ The rabbits receiving mivacurium and rocuronium had a significantly accelerated recovery from neuromuscular blockade compared with the placebo group in the immobilized limb after the immobilized duration, whereas there were no differences in the contralateral limb. The results of the present study showed that immobilization disuse atrophy produced by casting led to the development of resistance to both mivacurium and rocuronium; however, no resistance was shown in the contralateral limb. The peripheral nerve stimulator could be applied on the nonimmobilized limb, which might be associated with a normal recording if either mivacurium or rocuronium was used as neuromuscular relaxants.
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Anesthesia and analgesia · Feb 2003
Prognostic significance of postoperative in-hospital complications in elderly patients. I. Long-term survival.
To determine the impact of in-hospital postoperative complications on long-term survival, we prospectively studied consecutive patients > or = 70 yr of age undergoing noncardiac surgery. Potential clinical risk factors were measured and evaluated for their association with the occurrence of long-term postoperative mortality. Long-term survival was determined by using the Kaplan-Meier method. ⋯ A history of cancer (hazard ratio [HR] 2.44, 95% confidence interval [CI] 1.78-3.38, P < 0.0001), ASA physical status >II (HR 2.27, 95% CI 1.61-3.21, P < 0.0001), neurologic disease (HR 1.59, 95% CI 1.13-2.24, P = 0.008), age (HR 1.42 per decade, 95% CI 1.11-1.81, P = 0.005), postoperative pulmonary complications (HR 2.41, 95% CI 1.30-4.48, P = 0.005), and renal complications (HR 6.07, 95% CI 2.23-16.52, P < 0.0001) were significant independent predictors of decreased long-term survival. Compared with the United States population, patients with complications had a greater increase in mortality risk in the first 3 mo after surgery (HR 7.3 versus general population) than those without complications (HR 2.9, P = 0.023). An effort to improve perioperative care delivery to elderly surgical patients must include measures to minimize in-hospital postoperative complications, particularly those involving the pulmonary and renal systems.
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Anesthesia and analgesia · Feb 2003
Salicylate action on medullary inspiratory neuron activity in a brainstem-spinal cord preparation from newborn rats.
Salicylate affects central respiratory control. The inspiratory neurons are the most important component of the medullary respiratory control center because they modulate the final motor output via the phrenic nerve. We investigated changes in burst rate, intraburst firing frequency, and membrane properties of inspiratory neurons in the isolated brainstem after the administration of salicylate. ⋯ Resting membrane potential and intraburst firing frequency did not change with the application of salicylate and bicuculline even when the burst rate did change. We conclude that the effects of salicylate on the medullary inspiratory neurons are mainly due to a presynaptic action. GABAergic mechanisms are probably involved in the salicylate-induced central respiratory depression.